ChemInform Abstract: Microwave Spectrum of Methyliodosilane: Determination of the Dipole Moment and eqQ of an Asymmetric Top Molecule Containing an Atom with a Large Nuclear Quadrupole Moment.

Abstract

Abstract Microwave spectra of methyliodosilane and its deuterated species have been measured. A least-squares analysis for the observed frequencies yielded rotational constants and quadrupole coupling constants of the parent species as: A = 14 747.837 ± 0.054, B = 1893.504 ± 0.003, C = 1728.518 ± 0.003, χ aa = −1012.65 ± 0.43, η a χ aa = χ bb − χ cc = −161.96 ± 0.37, and | χ ab | = 478.29 ± 0.84 (all in MHz). The dipole moment of the parent species was determined from Stark effect measurement of some hyperfine components of the 3 03 -2 02 transition to be μ l = 1.862 ± 0.005, μ a = 1.831 ± 0.005, and μ b = 0.336 ± 0.005 D. Also the product among μ a , μ b , and χ ab was concluded to have a positive sign from the Stark shift observed. A brief discussion has been given on the procedure for determining the dipole moment of a molecule containing an atom with a large nuclear quadrupole coupling moment.